Appendix II. 195 



Now if this is shown to be the case with breeds the purest of 

 which have been adapted to their habitats and modes of life 

 during some few hundred years only, what shall we say when the 

 question is of a breed which has had a constant mode of life in 

 the same locality for ten thousand years or more, like the quagga ? 

 In this the stability of constitution must be such as no domestic 

 animal can approach. Relatively stable as may have been the 

 constitutions of Lord Morton's horses, as compared with the 

 constitutions of ordinary horses, yet, since Arab horses, even in 

 their native country, have probably in the course of successive 

 conquests and migrations of tribes become more or less mixed, 

 and since they have been subject to the conditions of domestic 

 life, differing much from the conditions of their original wild life, 

 and since the English breed has undergone the perturbing 

 effects of change from the climate and food of the East to the 

 climate and food of the West, the organizations of the horse and 

 mare in question could have had nothing like that perfect balance 

 produced in the quagga by a hundred centuries of harmonious 

 co-operation. Hence the result. And hence at the same time 

 the interpretation of the fact that analogous phenomena are not 

 perceived among domestic animals, or among ourselves ; since 

 both have relatively mixed, and generally extremely mixed, con- 

 stitutions, which, as we see in ourselves, have been made 

 generation after generation, not by the formation of a mean 

 between two parents, but by the jumbling of traits of the one 

 with traits of the other, until there exist no such conspiring 

 tendencies among the parts as cause repetition of combined 

 details of structure in posterity. 



Expectation that scepticism might be felt respecting this 

 alleged anomaly presented by the quagga-marked foal, had led 

 me to think over the matter ; and I had reached this inter- 

 pretation before sending to the College of Surgeons Museum 

 (being unable to go myself) to obtain the particulars and refer to 

 the records. When there was brought to me a copy of the 

 account as set forth in the " Philosophical Transactions," it was 

 joined with the information that there existed an appended 

 account of pigs, in which a parallel fact had been observed. 

 To my immediate inquiry — " Was the male a wild pig ? " — there 

 came the reply : ft I did not observe." Of course I forthwith 



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